Syslinux - Aug 2022 - Is Syslinux still in active development?

On 12 Aug 2022 at 17:03, Turritopsis Dohrnii Teo En Ming
wrote:
>
> I found that Syslinux is being used in many Linux distro ISO
> installers. I am just surprised that there have been no new releases
> for the past 8 years.
> 
Again, speaking my own mind, not from a position of authority:

Yes indeed, the particular "personality" of syslinux, called 
isolinux, has been used to boot from ISO CD/DVD media in legacy BIOS 
mode for many years. The alternative would probably be the "floppy 
emulation boot" = an even older style, allowing you to load the 
kernel in yet other ways... Isolinux uses the so-called "no-emulation 
boot", which once was the progressive way (two decades ago?) and is 
probably the most popular bootloader with that capability.

Note that legacy BIOS has been deprecated for how long... a decade, 
or thereabouts? And during that time, it has not developed any 
longer. Definitely not in those aspects / interfaces that are used by 
syslinux.
UEFI has fought hard to take over the rule, and has managed that a 
few years ago in the office and in the datacenter, and the time has 
probably come as well by now in the industrial/embedded PC segment 
(which has struggled, in the best tradition of its inertia / 
resistance to change).

With UEFI, all the "firmware services" are different, and the boot 
media format is different too - I mean the elements related to the 
boot sequence, the chain-loading of bootloader stages, the software 
interfaces involved.

Apparently, other bootloaders were quicker to pick up that UEFI 
gauntlet.

I mean to say that unless HPA et al have too much time on their hands 
(which they probably do not), there's not much point in converting 
syslinux to UEFI. I'd agree that competition is healthy and nice to 
have, but with UEFI the air of open firmware interfaces has gotten 
somewhat bittersweet. I cannot blame anyone that he doesn't want to 
code against that as a hobby. Even speaking of coding as a hobby, 
there are other areas that are more fun and bring more satisfaction.

So... other than this front of progress (follow suit and convert to 
UEFI), during the years, Syslinux has kept adding various goodies and 
capabilities on other fronts. I myself have stayed with PXElinux 3.x 
for a long time. Newer versions have brought some eye candy and 
actual useful features, but e.g. the new menu style and graphics (in 
v5/v6) have never quite worked for me, so I gave up on those 
upgrades. I need the bootloader to do its core job first and foremost 
= reliably load my OS images and work reliably across a wide variety 
of hardware.

Technical progress can be a nuissance, and it just happens :-)

The CD/DVD/ISO is nowadays legacy technology, just like the BIOS.
Does anyone still burn CD's nowadays? How many new machines still 
have optical drives? Rather, I tend to observe people flashing 
ISO9660 images onto USB thumb drives, which feels to me like fitting 
a square peg into a circular hole. Makes me wonder how isolinux still 
fits in there somewhere :-)
Booting off an emulated CD drive in a virtualized environment, where 
you just submit the ISO image file, and there's no quirky physical 
optical hardware involved - that works nicely, and will probably be 
with us for quite some time. With those of us who still maintain our 
own servers, even if virtualized, not necessarily on premises...

Frank

On Fri, 12 Aug 2022 at 17:43, Frantisek Rysanek
<Frantisek.Rysanek at post.cz> wrote:
>
> On 12 Aug 2022 at 17:03, Turritopsis Dohrnii Teo En Ming wrote:
> >
> > I found that Syslinux is being used in many Linux distro ISO
> > installers. I am just surprised that there have been no new releases
> > for the past 8 years.
> >
>
> Again, speaking my own mind, not from a position of authority:
>
> Yes indeed, the particular "personality" of syslinux, called
> isolinux, has been used to boot from ISO CD/DVD media in legacy BIOS
> mode for many years. The alternative would probably be the "floppy
> emulation boot" = an even older style, allowing you to load the
> kernel in yet other ways... Isolinux uses the so-called "no-emulation
> boot", which once was the progressive way (two decades ago?) and is
> probably the most popular bootloader with that capability.
>
> Note that legacy BIOS has been deprecated for how long... a decade,
> or thereabouts? And during that time, it has not developed any
> longer. Definitely not in those aspects / interfaces that are used by
> syslinux.
> UEFI has fought hard to take over the rule, and has managed that a
> few years ago in the office and in the datacenter, and the time has
> probably come as well by now in the industrial/embedded PC segment
> (which has struggled, in the best tradition of its inertia /
> resistance to change).
>
> With UEFI, all the "firmware services" are different, and the
boot
> media format is different too - I mean the elements related to the
> boot sequence, the chain-loading of bootloader stages, the software
> interfaces involved.
>
> Apparently, other bootloaders were quicker to pick up that UEFI
> gauntlet.
>
> I mean to say that unless HPA et al have too much time on their hands
> (which they probably do not), there's not much point in converting
> syslinux to UEFI. I'd agree that competition is healthy and nice to
> have, but with UEFI the air of open firmware interfaces has gotten
> somewhat bittersweet. I cannot blame anyone that he doesn't want to
> code against that as a hobby. Even speaking of coding as a hobby,
> there are other areas that are more fun and bring more satisfaction.
>
> So... other than this front of progress (follow suit and convert to
> UEFI), during the years, Syslinux has kept adding various goodies and
> capabilities on other fronts. I myself have stayed with PXElinux 3.x
> for a long time. Newer versions have brought some eye candy and
> actual useful features, but e.g. the new menu style and graphics (in
> v5/v6) have never quite worked for me, so I gave up on those
> upgrades. I need the bootloader to do its core job first and foremost
> = reliably load my OS images and work reliably across a wide variety
> of hardware.
>
> Technical progress can be a nuissance, and it just happens :-)
>
> The CD/DVD/ISO is nowadays legacy technology, just like the BIOS.
> Does anyone still burn CD's nowadays? How many new machines still
> have optical drives? Rather, I tend to observe people flashing
> ISO9660 images onto USB thumb drives, which feels to me like fitting
> a square peg into a circular hole. Makes me wonder how isolinux still
> fits in there somewhere :-)
> Booting off an emulated CD drive in a virtualized environment, where
> you just submit the ISO image file, and there's no quirky physical
> optical hardware involved - that works nicely, and will probably be
> with us for quite some time. With those of us who still maintain our
> own servers, even if virtualized, not necessarily on premises...
>
> Frank
>
I recall I had extremely difficulty with booting up my Linux From
Scratch with Syslinux a few years ago. Let me try to find that record
and get back here again.

Rgds,

Mr. Turritopsis Dohrnii Teo En Ming
Targeted Individual in Singapore

Hi,

Turritopsis Dohrnii Teo En Ming wrote:
> I found that Syslinux is being used in many Linux distro ISO
> installers.
The community of distro ISO producers is very slow with adopting new
things while the old stuff still works.

This is solidified by experience, e.g. the fact that switching away from
the ISO boot equipment and partition layout of Matthew J. Garret's
BIOS,EFI x DVD,USB-Stick ISOs always leaves behind some old machines or
odd EFI implementations. Sometimes because GRUB2's BIOS-related software
does not work well with a particular firmware implementation, sometimes
because firmware has particular non-standard expectations towards the
partitioning.

But the inactivity of the SYSLINUX project and its lack of support for
booting via EFI from CD/DVD/BD made GRUB2 necessary for about any distro.
I.e. the configuration files had to be translated from SYSLINUX to GRUB2
already.
So from the view of distro ISO producers it makes sense to use GRUB2 for
both, PC-BIOS and EFI. Further, they get support requests for adding
partitions to USB sticks with their ISOs, which means that they need to
clean up the partition tables in the ISOs and thus necessarily already
lose most of the victims of a switch to a pure GRUB2-bootable ISO.

Afterwards it's not much of a risk to give up the use of ISOLINUX.


Frantisek Rysanek wrote:
> The alternative [to ISOLINUX] would probably be the "floppy
> emulation boot" = an even older style, allowing you to load the
> kernel in yet other ways... Isolinux uses the so-called "no-emulation
> boot", which once was the progressive way (two decades ago?) and is
> probably the most popular bootloader with that capability.
GRUB2 provides a no-emulation boot image for El Torito which is equivalent
to isolinux.bin . Similarly to isolinux it needs some help from the ISO
producing program (see -boot-info-table in man mkisofs/genisoimage/xorrisofs
and --grub2-boot-info in man xorrisofs).

There is also a piece of MBR code, equivalent to isohdpfx.bin of ISOLINUX,
which lets PC-BIOS hop onto the El Torito boot image if the ISO is presented
on a USB stick.

No-emulation is the only non-legacy mode of El Torito. The others emulate
booting by images of a floppy (1200 1200 KiB, 1440 KiB, 2880 KiB) or a
hard-disk (size given by its MBR partition table) which are stored on a
CD-ROM.

> UEFI has fought hard to take over the rule, and has managed that a
> few years ago in the office and in the datacenter,
But SeaBIOS still seems to rule parts of the world of virtual machines in
datacenters. At least i witnessed some backtalk when producers of
installation ISOs brought up the idea to give up BIOS completely.

> Apparently, other bootloaders were quicker to pick up that UEFI
> gauntlet.
SYSLINUX EFI software seems to work well from hard disk and USB stick.
But its inaptness with optical media led to the rise of GRUB2 for ISOs
and now drives out many of the remaining ISOLINUX usages.

> The CD/DVD/ISO is nowadays legacy technology
Yes. I was told this when i started to work on that topic in 2006.

> Does anyone still burn CD's nowadays?
Me. One CD-RW every 8 days. It's hard to find a backup job which fits
into 700 MiB. Mine logs DVD or BD backups which happen every second day.

> I tend to observe people flashing
> ISO9660 images onto USB thumb drives, which feels to me like fitting
> a square peg into a circular hole.
Not necesarily. The potato shape of contemporary distro ISOs comes from
the quirks of old and new firmware. It is perfectly possible to make
a circular ISO. Fedora decided to do so with its version 37.
(There was also talk to give up ISO 9660 in favor of disk filesystems, but
this did not yield changes yet.)

But, as described above, any change in the first stage of the boot equipment
risks problem with legacy hardware and oddly programmed newcomers.
(I suspect that newcomers test their firmware with existing ISOs and so
train it to stick with their potato properties.)

Then there is the fact that ISO 9660 is essentially read-only, especially to
the noobs who elsewise fiddle with anything they can change.
Together with the movement towards neater partition tables this has appeal
for the distro ISO producers.


Have a nice day :)

Thomas